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Effect of Tumor Necrosis Factor-αon Expression of Skeletal Muscle Proteasome Subunit C2 in Rats with Chronic Obstructive Pulmonary Disease

Objective To study the effect of tumor necrosis factor-α( TNF-α) onhypermetabolism of skeletal muscle protein in rats with chronic obstructive pulmonary disease ( COPD) and explore its underlying mechanism. Methods Forty-five SD rats were randomly divided into a normal control group, a COPD group and a COPD + TNF-α group, with 15 rats in each group. COPD model was established by passive cigarette smoking in COPD group and COPD + TNF-αgroup. Then the extensor digitorium longus muscles ( EDL) were dissected and incubated in vitro muscle incubation system with adequate oxygen supply. The EDL were either cultured with or without recombinant rat TNF-α( 10 μg/L) . The mRNA and protein expressions of proteasome subunit C2 in EDL were quantified by real-time quantitative PCR and Western blot analysis, respectively. Results The mRNA and protein expressions of proteasome subunit C2 were both significant higher in the COPD group and COPD + TNF-αgroup than those in the normal control group( P lt;0. 01 or 0. 05) . The COPD+TNF-αgroup had higher expression of proteasome subunit C2 mRNA than that in the COPD group( P lt; 0. 01) , whereas the protein expression was not significantly different( P gt; 0. 05) . Conclusion Incresed proteolytic metabolism in skeletal muscle in COPD might be regulated by TNF-αactivated ubiquitin-dependent pathway.

Inhibition of liposome-mediated recombinant plasmid expressing small interference RNA targeting hypoxia-induced factor-1α on retinal neovascularization in mice

Objective To observe the inhibition of LipofectamineTM2000 (LF2000)mediated pSUPER recombinant plasmid expressing small interference RNA targeting hypoxia-induced factor (HIF)-1alpha;(pSUPERsiHIF-1alpha;) on retinal neovascularization in mice. Methods pSUPERsiHIF-1alpha; recombinant plasmid was created. Forty-eight (seven-day-old) C57BL/6J mice were randomly divided into a normal group, the control group, empty vector group and gene therapy group with 12 mice in each group. Mice in the normal group were kept in normal room air, while the other three groups retinal neovascularization was induced by hypoxia. The mice in control group were not treated. The mice in the vector group received intravitreous injection of pSUPER and LF2000 (1 mu;l), and the gene therapy group received pSUPERsiHIF-1alpha; and LF2000 (1 mu;l)one day before being returned to normal room air．Fluorescent angiography was used to assess the vascular pattern. The proliferative neovascular response was quantified by counting the nuclei of new vessels extending from the retina into the vitreous in cross-sections．HIF-lalpha;and vascular endothelial growth factor (VEGF) levels in retinas were measured by immune histochemical staining method and reverse transeriptase-polymerase chain reaction (RT-PCR). Results Fluorescent angiography showed radial branching pattern vessels in the normal group and distorted large vessels, obstructed capillaries, many neovascular tuffs, fluorescence leakage in the peripheral retina in the control group and vector group. The gene therapy group demonstrated a significant reduction in neovascular tufts and fluorescence leakage compared with the control group and the vector group. The number of vascular cell nuclei extending breaking through the internal limiting membrane(ILM) of control group and vector group increased significantly compared with normal group (F=5850.016,P＜0.05), while obviously decreasing in the gene therapy group compared with control group (F=3012.469,P＜0.05). Immunohistochemical staining showed the expression of HIF-1alpha; protein in nucleus and VEGF protein in cytoplasm. The expression of HIF-1alpha; protein in retina was negative, while VEGF protein was weakly positive in normal group. The expression of HIF-1alpha; and VEGF protein were both positive in control group and vector group, while weakly positive in gene therapy group. The Results of RT-PCR showed that the expression of HIF-1alpha; mRNA in retina was increased significantly in control group and vector group as compared with normal group (F=3102.326,P＜0.05), while decreasing significantly in gene therapy group as compared with control group (F=3336.425,P＜0.05). Conclusion Retinal neovascularization in the mice is significantly inhibited by intravitreal injection of LF2000-mediated recombinant plasmid pSUPERsiHIF-1alpha;.

Effects of 17β-estradiol on the oxygen-induced retinal neovasularization in rat

Objective To investigate the effects and mechanism of 17β-estradiol on the retinal neovasularization in rats with oxygen-induced retinopathy (OIR). MethodsA total of 48 SD rats were randomly divided into control group A, control group B, experimental group A and experimental group B with 12 rats in each group. The rats in control group A and experimental group A received a hypodermic injection of 0.1 ml PBS, and the rats in control group B and experimental group B group received an a hypodermic injection of 0.1 ml 17β-estradiol. At postnatal day 7 (P7) and P14, the mRNA expression of vascular endothelial growth factor (VEGF) and Hypoxia-inducible factor (HIF) -1α in the retina were measured by real-time polymerase chain reaction (RTPCR). At P14, endothelial cell nuclei breaking through the internal limiting membrane were counted after staining with hematoxylin and eosin (HE), and the protein expression of VEGF was measured after immunohistochemical staining. The changes of retinal ultrastructure were observed by transmission electron microscopy. ResultsAt P14, the difference of the number of endothelial cell nuclei among four groups was statistically significant(F=10.7, P＜0.05). The number of endothelial cell nuclei in experimental group A was increased greater than that in control group A (P＜0.05) and experimental group B(q=5.16，P＜0.05). But there was no difference between control group A and experimental group B (q=0.25，P＞0.05). The difference of VEGF protein expression among the four groups was statistically significant (P＜0.05). Comparing experimental group A with control group A, B and experimental group B, the difference was statistically significant (P＜0.05). In experimental group A there was ganglion cell swelling, pale staining cytoplasm and mitochondria vacuolizationin, while these were normal in other three groups. At P7 and P14, the differences of VEGF and HIF-1 mRNA expression among four groups were statistically significant(F=14.7,16.1, 13.4, 17.5; P=0.001, 0.005, 0.003, 0.009). At P7, the VEGF mRNA expression in control group B was more than that in control group A (q=5.22, P＜0.05). The VEGF mRNA expression in experimental group B was more than that in experimental group A (q=4.32, P＜0.05). At P14, the VEGF mRNA expression in control group B was more than that in control group A (q=3.72, P＜0.05), but there was no difference of HIF-1 mRNA expression between two groups. The VEGF and HIF-1 mRNA expression in experimental group B were both decreased more than those in experimental group A (q=5.12, 4.08;P＜0.05). Conclusions 17β-estradiol has the effect of two way regulation in VEGF mRNA, which increases VEGF expression in retina under hyperoxic conditions so as to develop the vascular system; which reduces VEGF and HIF-1α expression so as to prevent pathologic neovascularization under hypoxic conditions. It provides some protection from the damage of retinal neovascularization.

Hypoxia inducible factor 1α regulates the expression of CD18 in the early stage of diabetic retinopathy

Objective　To observe the effect of hypoxia inducible factor-1alpha;（HIF-1alpha;）to the expression of cell surface adhesion molecules CD18 and the adhesion ability of leukocytes and vascular endothelial cells under early stage of diabetic retinopathy condition.Methods　The human promyelocytic leukemia cell line HL60 and the rhesus choroid-retina vascular endothelial cell line RF/6A were cultured in RPMI 1640 medium-10% human serum, which was collected from the subjects of early stage of diabetic retinopathy and age-matched healthy control. The cells were cultured in 4 groups as control group (group A), diabetic group (group B), HIF-1 anti-sense oligonucleotides (ASODN) group (group C) and HIF-1 sense oligonucleotides (SODN) group (group D). The percentages of CD18 positive cell in the HL60 cell were measured by flow cytometry and mRNA in the HL60 cell by realtime reverse transcriptionpolymerase chain reaction（RT-PCR）. Results　The percentage of CD18 positive cell in the group A, B, C and D was 17.06plusmn;6.01, 42.23plusmn;2.60, 25.33plusmn;3.05 and 32.40plusmn;10.57, respectively, the differences among them were significant (F=36.47,P＜0.001). Compared to the group A,the expression of CD18 mRNA in the group B,C and D was increased about 21.05plusmn;2.07、2.23plusmn;0.96 and 25.07plusmn;2.27 times,respectively, the differences among them were significant (F=180.34, Plt;0.001). The adherent rates of HL60 to RF/6A in group A, B, C and D was 0.06plusmn;0.00,0.09plusmn;0.10,0.05plusmn;0.00 and 0.07plusmn;0.01, respectively,the differences among them were significant（F=13.06，P=0.002）.Conclusion　In vitro, HIF-1 could regulate the expression of CD18 by HL60, and the adhesion of HL60 to RF/6A when the cells were exposed to diabetic serum. The effects of human serum weaken with the inhibition of HIF-1 expression.HIF-1 play regulatory role in the expression of CD18 and adhesion of leukocytes and vascular endothelial cells under early stage of diabetic retinopathy condition.

The expression of hypoxia inducible factor -1αin embryonic and postnatal rats′retinae

Objective To investigate the expression of hypoxia inducible factor 1(HIF1alpha;) in ratsprime; retinae during the embryonic and earlier postnatal period. Methods The retinal expression patterns of HIF-1alpha; protein and mRNA of embryonic day 12 (E12), E16, E20, and postnatal day 1(P1) and P5 rats were determined by immunohistochemical staining and reverse transcriptionpolymerase chain reaction (RT-PCR). Results HIF-1alpha; protein was detected in the neural epithelial layer and the pigment epithelial layer at all those 5 timepoints, with higher expression in the ganglion cell layer and the inner plexiform layer, and seems limited to the ganglion cell layer when re tina became more mature. Embryonic rat retina had higher expression of HIF-1alpha; protein and mRNA than postnatal retina, the difference was significant (P＜0.01）. Conclusion The expression of HIF1alpha; in ratsprime;retina e differs from embryonic to earlier postnatal stages. 

缺氧诱导因子-1α、血管内皮生长因子在视网膜母细胞瘤中的表达及意义

Influence of hypoxia-inducible factor-1α on the expression of neutrophil CD18 and leukocyte adhesion in diabetic rats

Objective To observe the influence of the expression of CD18 on the neutrophile and the leukocyte adhesion to retinal vascular endothelium by hypoxia-inducible factor-1 alpha (HIF-1alpha;) in early diabetic retinopathy rats. Methods Male Sprague-Dawley rats received intraperitoneal injection of streptozotocin to induce diabetes model. 18 diabetic rats were divided into 3 groups randomly after 2 months of diabetes induction, including diabetic group (group B), HIF-1alpha; anti-sense oligonucleotides (ASODN) injection group (group C) and HIF-1alpha; sense oligonucleotides (SODN) injection group (group D), the age and weigh matched health rats were chosen as control group (group A), with 6 rats in each group. Then group A and B rats received 5% glucose solution caudalis veins injection, group C and group D rats received HIF-1alpha; ASODN and HIF-1alpha; SODN caudalis veins injection, respectively(025 mg/kg).The level of CD18 on the neutrophil isolated from the peripheral blood was measured by flow cytometry. Retinal leukostasis was quantified with acridine orange leukocyte fluorography. Results The percentage of CD18 positive neutrophil cell was（44.93plusmn;3.60）% in group B，（18.66plusmn;1.52）% in group A，（31.66plusmn;4.72）% in group C，（51.00plusmn;5.66）% in group D. Compared with each other groups，the differences are statistically significant （F=42.46, Plt;0.001）. The number of positive staining cells of retinal leukocyte was （46.16plusmn;10.68）in group A，（133.83plusmn;20.43）in group B,（99.83plusmn;9.28）in group C，（121.33plusmn;10.23） in group C. Compared group B with group C，the number of positive staining cells raised about 2.89 times；compared group B with group C and D，the differences are statistically significant （P=0.12，95% confidence interval -3.69~28.69）. Conclusions In vivo, HIF-1alpha; can decreased the expression of CD18 on neutrophils from diabetic ratsprime; peripheral blood and the collection of retinal leukostasis in the diabetic animals. HIF-1alpha; may serve as a therapeutic target for the treatment and/or prevention of early diabetic retinopathy.  （Chin J Ocul Fundus Dis，2008，24：268-271）

Inhibition of expression of vascular endothelial growth factor by interfering RNA targeting hypoxia inducible factor1α and vascular endothelial growth factor in human vascular endothelial cells

Objective To investigate the effect of small interfering RNA(siRNA) targeting hypoxia inducible factor1alpha; (HIF1alpha;) and vascular endothelial growth factor (VEGF) on expression of VEGF in human vascular endothelial cells. Methods HIF-1alpha; siRNA recombinant plasmid was constructed. Human vascular ndothelial cells were cultured in vitro and divided into normoxia group (20% O2) and hypoxia group (1% O2). Hypoxia group was then divided into control group, vector group, HIF-1alpha; group (HIF-1alpha; siRNA), VEGF group ( VEGF165  siRNA) and cotransfection group (HIF-1alpha; siRNA+VEGF165 siRNA). LipofectamineTM 2000 (LF2000) mediated vector plasmid was transfected to cells in each group except the control group. The expression of HIF-1alpha; siRNA and VEGF165 siRNA recombinant plasmid were identified by reverse transcriptasepolymerase chain reaction (RT-PCR). The expression of VEGF mRNA and protein were detected by RTPCR and immunocytochemical method. Results The expression of HIF-1alpha; siRNA and VEGF165 si RNA recombinant plasmid were detected 24 hours after transfected. The expression of VEGF mRNA and protein was faint in the normoxia group, but increased obviously in hypoxia group. The expression of VEGF mRNA and protein in the HIF1alpha;, VEGF and cotransfection groups were lower than which in the control group. Cotransfection group showed the highest inhibitory effect. Conclusion HIF-1alpha; and VEGF165 siRNA can effectively inhibit the expression of VEGF in human vascular endothelial cells.

Promotion of Pink1S Auto-phosphorylation with CK2β

The aim of this study is to determine the regulatory mechanism of PTEN-induced putative kinase protein 1 short isoform (PINK1S) in cytoplasm. By co-immunoprecipitation (Co-IP) assay, we identified that PINK1S interacted with the beta regulatory subunit of Casein Kinase 2 (CK2β), but not with the catalytic subunits CK2α1 and CK2α2. Furthermore, cells were transfected with PINK1S and CK2β, and then PINK1S was purified by immunoprecipitation. After detecting the phosphorylated proteins by Phos-tagTM Biotin, we found that CK2β overexpression increased auto-phosphorylation of PINK1S. Finally, we generated CK2β knockdown cell lines by RNA interference. Purified PINK1S from CK2β knockdown cells significantly reduced its auto-phosphorylation compared with control cells. These results suggested that CK2β functions as a regulatory subunit of PINK1S kinase complex promoted its activation by self-phosphorylation.

臭氧对糖尿病大鼠视网膜结构及缺氧诱导因子-1α表达的影响